Proper venting of gasoline fuel tanks in cars or vehicles is important to reduce emissions of hydrocarbon fuels into the atmosphere and thus to reduce pollution of the atmosphere. Disclosure is made of a fuel tank cap, with controlled venting both into and out of the fuel tank, and a gasket sealing the cap to the fill pipe of the fuel tank, and the vents maintain minimum ventage of the hydrocarbon fuel vapors.
Disclosure is made of a car or vehicle fuel cap having an inlet vent valve and an outlet vent valve and each vent valve held in closed position until activated to open position by a pressure differential of pressure build up in the fuel tank for the outlet vent valve to open or the inlet vent valve actuated by negative pressure in the fuel tank, and the vent valves can be described as umbrella shape check valves, or reed valves as alternates to the umbrella valves. This invention then obviates the use of coil compression springs as now used in fuel caps for vent controls.
An object of this invention is to disclose and claim a vehicle fuel cap having an inlet vent and an outlet vent and the outlet vent extending upwards, held in closed position by an umbrella shaped cover extending over the vent aperture, and the edges of the umbrella shaped cover riding on the periphery around the outlet vent aperture and the umbrella shaped cover held in position over the outlet vent by fastening of the umbrella shaped cover onto a pillar extending from the vent aperture surface to the center of the concave surface of the umbrella shaped cap, and an inlet aperture extending downward in the fuel cap, and a pillar extending downward next to the inlet aperture and an inverted umbrella shaped cover extending over the inlet aperture, and the inverted umbrella shape cover attached to the pillar and the edge of the concave shape of the inverted umbrella shape extending over the inlet vent aperture.
Another object is to disclose and claim, as an alternate to umbrella shaped valves, reed valves in a fuel cap, and one reed valve in an outlet vent aperture and one reed valve in the inlet aperture, and the reed valves actuated by differential pressures inside and outside of the fuel tank.
U.S.Patents:
U.S. Pat. No. 4,337,873 for FUEL CAP WITH POPPET VALVES. Spring loaded valves are disclosed.
U.S. Pat. No. 4,436,219 for SEALING CAP FOR GAS TANK. Pressure and vacuum relief valves are shown
U.S. Pat. No. 4,765,505 for DELAYED ACTUATION FUEL CAP. The lost motion of the hub to break the seal on the fill pipe.
U.S. Pat. No. 5,108,001 for PRESSURE RELEASE VENT CAP. Spring loaded vents are disclosed.
U.S. Pat. No. #5,996,829 for FUEL TANK CAP. Disclosure is made of a fuel tank cap to control the pressure in a fuel tank by opening and closing a rubber valve.
U.S. Pat. No. #6,003,709 for FUEL CAP. Electrically conductive fuel cap.
None of the above cited patents anticipate or make obvious the disclosure and claims of this present invention.